The invention relates generally to an arrangement for projecting data onto radiation-sensitive material.
More particularly, the invention relates to an arrangement for projecting data onto film, especially X-ray film. Examples of such data and the time of day the film was exposed and, for X-ray films of humans, the names of the patient and the physician in charge.
German Pat. No. 2,021,494 discloses an arrangement which can be used to project images of data from a data carrier card onto an X-ray film while the film is confined in a cassette. A cassette of the type to be used in the apparatus of the German patent is provided with a window which can be sealed against entry of radiation. The apparatus of the German patent is equipped with means for opening the window of the cassette and with means for imaging data onto that portion of the film which is exposed in response to opening of the window. The information which is imaged onto the film portion behind the window may include the time of day the film was exposed. To this end, the apparatus of the German patent comprises a timer disc which is driven by a motor. The timer disc is mounted adjacent the data carrier card so that the image of the disc can be projected onto the film together with the data from the data carrier card.
The above- referenced, commonly-owned U.S. Pat. application Ser. No. 205,996 also discloses an arrangement for projecting data onto X-ray film. The arrangement has a support which receives a cassette for a sheet of film. The cassette has a window which is normally sealed against radiation but may be opened to expose a portion of the film to be image of data carried by a data carrier. The data carrier is in the form of a card and the arrangement is capable of supporting the card in either of two mutually perpendicular positions in which the portion of the card having the data is exposed. A light source is provided to illuminate the data-carrying portion of the card in either of the two positions of the latter. A partially light-transmissive mirror is arranged at an angle of 45.degree. to both of the positions of the card. The mirror reflects a portion of the light from the light source to one of the positions of the card and transmits the light returning from this position to the film. The mirror furthers transmits a portion of the light from the light source to the other position of the card and reflects the light returning from this position to the film. A lens for focusing the imge of the data onto the film is positioned on the optical axis of one of the two possible positions of the data-carrying portion of the data carrier card.
Arrangements of the above type are generally used to record personal and/or other data on X-ray films of humans.
An X-ray film showing a human heart is usually examined in such a manner that the heart of the patient is located on the right-hand side of the film. In other words, the physician observes the film as if he or she were facing the patient. However, the patient may be X-rayed from the back or the front. In the former case, the X-rays travel from the back of the patient towards the front and a p-a (postero-anterior) X-ray picture results. In the latter case, the X-rays travel from the front of the patient towards the back and an a-p (antero-posterior) X-ray picture results.
The imaging of data such as the name of the patient, the name of the physician, etc. onto the film may be performed either before or after the patient is X-rayed and replaces the laborious procedure of writing the information on the film after development. In order for the data to be properly oriented when the physician reads the film, it is necessary to image the data onto the film differently depending upon whether the film represents a p-a or an a-p picture. It is to this end that the above-referenced, commonly-owned U.S. Pat. application Ser. No. 205,996 proposes that the projection arrangement be designed to accept the data carrier card in either of two different orientations. Furthermore, as discussed earlier, a partially light-transmissive mirror is provided and is used for both orientations of the card. In one orientation of the card, light from the light source is reflected to the card by the mirror and the image of the data is then transmitted through the mirror to the film. In the other orientation of the card, light from the light source is transmitted through the mirror to the card and the image of the data is subsequently reflected to the film by means of the mirror. In the first case, the image of the data is inverted once, namely, by the focusing lens. In the second case, the image is inverted by the mirror and then once more by the focusing lens. Accordingly, appropriate selection of the orientation of the card permits the data to be recorded on the film in the correct orientation regardless of whether the film represents a p-a or an a-p picture.
It has been found that the arrangement of the above-referenced, commonly-owned U.S. Pat. application Ser. No. 205,996 does not provide entirely satisfactory illumination of the data carrier card in either of the orientations of the latter.